In large facilities such as assembly plants or the like, the efficient movement of materials, parts, subassemblies, etc., from one location to another may be extremely important task to the overall function of the facility. For example, an unintended assembly plant assembly line stoppage generally results in significant lost revenue. Consequently, each station on an assembly line must be fed with an adequate supply of materials to keep the line moving without unintended stoppages.
Complicating matters, however, is the fact that today's streamlined production and workflow models do not allow for large volume inventory (e.g., parts) storage, so assembly line stations, etc., typically operate with a minimum of stored materials at any given time. One such method of note is ‘Right Parts in the Right Place at the Right Time’ (RPT) manufacturing. When practicing this type of distribution method, parts must move quickly from the supplier's factory to the final assembly line with little time and space wasted in between. It can thus be understood that in a large assembly plant that produces a high volume of outgoing products, moving thousands of parts to hundreds of different workstations can be a daunting task.
In order to meet low inventory production requirements, facilities often employ systems that are able to load and unload different types and sizes of containers from and onto a guided rail or roller system that functions to move the containers around the facility. In many factories, for example, containers of parts, fasteners, etc., may be transported throughout the factory by various tugger, tram or train systems that haul multiple cars/carts loaded with various containers. Typically, such distribution systems will try to minimize the amount of action required by human operators/workers, such as by employing lift-assist devices that allow works to lift and move heavy objects.
More advanced loading and unloading devices and systems have also been developed, such as those disclosed in U.S. application Ser. No. 12/240,889 filed on Sep. 29, 2008. These devices and systems allow a worker to quickly and easily load and unload a variety of different containers moved by a transportation system, such as containers located on one or a train of cars pulled by a tugger, automated guided vehicle (AGV), tram, etc.
While devices and systems like those described above have helped to streamline the process of moving materials about a facility, there is still room for improvement. For example, there remains a need for unloading devices and systems that can unload containers with less operator involvement—such as containers that have been transported to an unloading location by an automated transport system or some other means. Embodiments of the invention are directed to devices and systems that can perform such an unload function substantially or fully automatically.